My U.S. Pat. No. 4,077,126 (the disclosure of which is incorporated herein by reference) shows an orthodontic bracket with a rotatable locking member mounted within a body portion of the bracket. Reference is made to my earlier patent for a discussion of the function of an orthodontic bracket, and the problems inherent in using conventional brackets which require installation of tie or ligature wires to secure an arch wire to the bracket.
The new bracket herein disclosed is an improvement on the locking bracket described in the aforementioned patent. The new assembly is preferably of two- or three-piece construction, including a base, an open-slotted bar integrally formed with or adapted for attachment to the base, and a locking member which is rotatably mounted on the bar. The locking member is preferably captured between supporting bearing surfaces on the base and bar, and the bar can be positioned during assembly to provide a corrective torque force to the tooth on which the bracket is to be mounted.
The rotatable locking member eliminates need for ligature wires at most or all stages of orthodontic treatment, but provision is made for use of ligatures if the tooth is so severely malpositioned that seating of the arch wire in the bracket cannot be achieved during early treatment. When reasonable tooth alignment is present, ligatures are eliminated, and the arch wire is installed and exchanged between treatment phases simply by rotating the locking members of the affected brackets to an open position.